It would seem as though under ordinary circumstances occasional oiling would be adequate, but this is 'The Saddle Time Forgot'. I'll guarantee my sister-in-law never oiled it during its brief use, then it sat in a garage for 33 years where temperatures in summer would've routinely passed 100 degrees, and humidity was very low. It's a safe bet whatever oils or moisture were present in the hide when it was new have long since been slow-cooked out. To just pick up with normal maintenance after all that time couldn't be enough -- it'll need some sort of extra measures to catch up again.
I'm thinking it might be good to use the moulded aluminum-foil 'pan' technique and give it a thorough soak in Proofide, then go back to a normal oiling routine. The rural areas where I live are fairly 'horsey'; a saddler or tack shop might also be a good place to get some input.
An amusing footnote: My wife and her delicate posterior are no fans of Brooks saddles, preferring instead her foo-foo mattress saddle, so the B72 came off the Raleigh and directly onto my gold '68 Motobecane, where it looks much more appropriate than the gel saddle that it had when I got it.